1. Technical Field
The present invention relates to well servicing devices and systems, and particularly to devices and systems used in servicing petroleum and gas producing wells.
2. Background Art
Often during oil well servicing, fluids spill from the wellhead. Early containment practice of such spills consisted of digging a pit around the wellhead. Environmental and regulatory concerns effectively discouraged such practice, leading to the need for alternate means to contain liquid spilled during well servicing. To date, devices and methods used to contain excess fluid spilled from a wellhead during servicing have suffered from several drawbacks. For example, among other things, such devices and methods generally: 1) obstruct the area around the wellhead thereby interfering with servicing; 2) include pans that require assembly at the well site or are cumbersome to install; 3) include pans that are constructed of separate pieces thereby being subject to leaks; and 4) where pumping means are used to transfer contained liquids away from the wellhead, such means involve electrical or internal combustion drives which, for safety reasons, must be located some distance away from the wellhead.
In view of the above described deficiencies associated with the use of known wellhead systems, the present invention has been developed to alleviate these drawbacks and provide further benefits to the user. These enhancements and benefits are described in greater detail herein below with respect to several alternative embodiments of the present invention.
The present invention in its several disclosed embodiments alleviates the drawbacks described above with respect to conventionally designed wellhead servicing devices and incorporates several additionally beneficial features.
In at least one embodiment, the present invention takes the form of a fluid collection system for connection above-ground upon a wellhead. The fluid collection system includes a fluid collection pan assembly defining an open fluid reservoir in an upper portion thereof, the pan assembly being connectable upon a wellhead so that produced fluids pass through and above the pan assembly for collection in the reservoir. A fluid withdrawal pump is connected in fluid communication with the reservoir and the fluid withdrawal pump is adapted to be hydraulically powered by a main hydraulic system of a well servicing rig already on site thereby avoiding the need for a supplementary hydraulic power source at the well site.
In a further embodiment, the invention takes the form of a fluid collection system for connection upon a wellhead. The collection system includes a fluid collection pan having an upwardly open fluid reservoir. The pan is adapted to be connected in-line with a wellhead conduit. The pan has an upwardly convex floor adapted to direct collected fluids in the reservoir toward a peripheral trough that is formed between the floor and a surrounding side wall to the floor. One or more drains is positioned at the trough for accommodating withdrawal of collected fluid therefrom. A wellhead extension conduit is included that has a through bore configured for conveying well produced fluids from below the fluid collection pan to above the fluid reservoir. Preferably, the extension conduit and the pan are unitarily configured to permit on-site monolithic installation of the assembly upon a wellhead.
The present invention mitigates obstruction of the wellhead. In addition to providing a wide pan that will capture fluids spilled from the wellhead during servicing, the present invention also includes a through hole in the pan for accommodating tool assemblies inserted in the servicing string. Further, the pan has a convex interior with two drain outlets placed at the pan""s outside edges, minimizing the obstruction from drain hosing.
As the pan is unitary in construction, it requires no assembly and is less susceptible to leaks than pans which require assembly. On its exterior perimeter, the pan is fitted with xe2x80x9cDxe2x80x9d flanges or eyes for facilitating its installation on the wellhead casing top. Support braces are also incorporated into the design of the pan for strengthening it, as well as providing an additional means for securing links used in placing the pan on the casing top.
The present invention""s pump for pulling fluids from the pan to the trailer tank is driven hydraulically and controlled pneumatically, allowing the entire system to be located inside the servicing unit""s safety perimeter. The pump""s hydraulic motor is driven by the well servicing unit""s hydraulic pump, which, in turn, is driven by the servicing unit""s own power take off (xe2x80x9cPTOxe2x80x9d) instead of an independent internal combustion motor or electrical source.
A single air valve controls the operation of the pan pump. Air for the valve comes from the servicing unit. The valve is able to be mounted near the well servicing unit""s operator, thereby enabling him to operate the collection system pump at will. The advantage to this type of hydraulic/pneumatic system is that it removes a potential fire hazard and permits the collection system to be closer to the servicing unit. With an independent internal combustion motor or electrically sourced pump, the servicing unit must be at least outside the servicing unit""s guy wires for fire safety reasons.
The beneficial effects described above apply generally to each of the exemplary devices and mechanisms disclosed herein of the wellhead system. The specific structures through which these benefits are delivered will be described in detail hereinbelow.